diff --git a/ngc_hs1.cpp b/ngc_hs1.cpp
index c614435..b6852ab 100644
--- a/ngc_hs1.cpp
+++ b/ngc_hs1.cpp
@@ -351,6 +351,13 @@ void NGC_HS1_record_own_message(
 	assert(ngc_hs1_ctx->history.count(g_id));
 }
 
+void NGC_HS1_register_callback_group_message(NGC_EXT_CTX* ngc_ext_ctx, NGC_HS1_group_message_cb* callback) {
+	assert(ngc_ext_ctx);
+	assert(ngc_ext_ctx->ngc_hs1_ctx);
+
+	ngc_ext_ctx->ngc_hs1_ctx->cb_group_message = callback;
+}
+
 // record others msg
 void NGC_HS1_record_message(
 	const Tox *tox,
@@ -566,6 +573,19 @@ void _handle_HS1_ft_recv_data(
 		peer.pending.erase(transfer.msg_id);
 		peer.append(transfer.msg_id, static_cast<Tox_Message_Type>(transfer.recv_buffer.front()), std::string(reinterpret_cast<const char*>(transfer.recv_buffer.data()+1)));
 
+		assert(ngc_ext_ctx->ngc_hs1_ctx->cb_group_message);
+		// we dont notify if we dont know the peer id. this kinda breaks some stuff
+		if (peer.id.has_value()) {
+			ngc_ext_ctx->ngc_hs1_ctx->cb_group_message(
+				tox,
+				group_number, peer.id.value(),
+				static_cast<Tox_Message_Type>(transfer.recv_buffer.front()),
+				transfer.recv_buffer.data()+1,
+				data_size-1,
+				transfer.msg_id
+			);
+		}
+
 		group.transfers.erase(std::make_pair(peer_number, transfer_id));
 	}
 }
diff --git a/ngc_hs1.h b/ngc_hs1.h
index 7774ef6..7e52376 100644
--- a/ngc_hs1.h
+++ b/ngc_hs1.h
@@ -80,11 +80,18 @@ void NGC_HS1_record_own_message(
 
 // ========== receive message ==========
 
-// !!! no shim, whould require global state !!!
-// shim (same interface)
-//typedef void tox_group_message_cb(Tox *tox, uint32_t group_number, uint32_t peer_id, Tox_Message_Type type,
-//const uint8_t *message, size_t length, uint32_t message_id, void *user_data);
-//void NGC_HS1_callback_group_message(Tox *tox, NGC_HS1* ngc_hs1_ctx, tox_group_message_cb *callback);
+typedef void NGC_HS1_group_message_cb(
+	Tox *tox,
+	uint32_t group_number,
+	uint32_t peer_id,
+	Tox_Message_Type type,
+	const uint8_t *message,
+	size_t length,
+	uint32_t message_id
+);
+
+// callback for when history sync has a new message
+void NGC_HS1_register_callback_group_message(NGC_EXT_CTX* ngc_ext_ctx, NGC_HS1_group_message_cb* callback);
 
 // record others msg
 void NGC_HS1_record_message(
diff --git a/ngc_hs1.hpp b/ngc_hs1.hpp
index 36ae442..4b1c700 100644
--- a/ngc_hs1.hpp
+++ b/ngc_hs1.hpp
@@ -17,7 +17,7 @@ struct NGC_HS1 {
 
 	// callbacks
 	//tox_group_message_cb* client_tox_msg_callback;
-
+	NGC_HS1_group_message_cb* cb_group_message {nullptr};
 
 	// key			- key			- key		- value store
 	// group pubkey - peer pubkey	- msg_id	- message(type + text)